1. Field of the Invention
The present invention relates to a trouble diagnosing device that diagnoses a trouble of a vehicle such as a track or a bus, as the device is coupled with an ECU (electronic control unit) mounted on the vehicle.
2. Description of the Related Art
As shown in FIG. 10, a trouble diagnosing device for an electronic control system of a vehicle is conventionally known. (See, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-91545) As shown in FIG. 10, a trouble diagnosing device 1 is connected via a communication line 2 to a vehicle-installed ECU 3 (electronic control unit). Various commands are transmitted and received between the trouble diagnosing device 1 and the ECU 3 via the communication line 2. For example, in the case where a vehicle equipped with the ECU 3 is of an air suspension type, a memory 4 for storing vehicle height data and air suspension pressure data is connected to the ECU 3. Further, an actuator (not shown) for opening/closing a valve that controls the charge and discharge of air to and from the air suspension is connected to the ECU 3.
The trouble diagnosis device 1 includes a display unit 5, an “S” key 6a, a “C” key 6b, a cursor key 7, an “YES” key 8a, a “NO” key 8b and function keys 9.
When a vehicle height adjustment mode is set in the trouble diagnosis device 1, an image for adjusting a front-side vehicle height is displayed on the display unit 5 as can be seen in FIG. 11A. The lowermost section of the display unit 5 displays an “UP” display portion, which indicates that the operation is set to a mode of raising the vehicle height, a “DOWN” display portion, which indicates that the operation is set to a mode of lowering the vehicle height, and a “FIX” display portion, which indicates that the operation is set to a mode of assigning the adjusted value as an initial value to the memory 4. The currently set mode is indicated by color reversion in black and white. That is, FIG. 11A shows a case where the mode of raising the vehicle height is set.
As a vehicle height adjusting mode, there is a neutral position setting mode for setting the vehicle height at a neutral position. In the neutral position setting mode, an operator keeps on pushing a particular key, for example, the “YES” key 8a, while measuring the vehicle height using a gauge, to transmit the command of raising the vehicle height to the ECU 3, and thus the vehicle is raised. When the vehicle height reaches the neutral position, the “YES” key 8a is released to stop the vehicle raising operation.
However, there is, for example, a time delay in the operation of the valve that controls charging and discharging of air to and from the air suspension, and therefore the supply of the air is not stopped immediately after releasing the “YES” key 8a. As a result, the front-side vehicle height, in some cases, becomes higher than the neutral position.
In these cases, the cursor key 7 is operated to revert the color of the “DOWN” display portion from black to white, and then the “YES” key 8a is pushed. In this manner, the vehicle height lowering operation is performed to adjust the height to the neutral position.
As described above, in the adjustment of the vehicle height, the raising and lowering of the height must be repeated, and the cursor key 7 must be manipulated each time to change the direction of the vehicle height adjustment. Thus, the operability is not good.
Further, since the vehicle height is adjusted while pressing the “YES” key 8a, an overshoot, which causes a vehicle height higher or lower than the neutral position, occurs in some cases for the following reason. That is, when the vehicle height reaches near the neutral position in an actual situation, the charge or discharge of air to or from the air suspension cannot be performed appropriately due to a time delay in the operation of the valve, causing the overshoot.
Moreover, as shown in FIG. 11B, a key must be manipulated in order to display the pressure data of the air suspension, resulting in a poor operability.